Machine for coating of articles



Oct. 17, 1950 P. WHITE MACHINE FOR comma 0F ARTICLES Original Filed Nov. 25, 1944 IN VEN TOR.

WWM /M Patented Oct. 17,

UNITED STATES I PATENT OFFICE MACHINE FOR COATING OF ARTICLES Percy White, Th nrcaston, Leicester, England, as-

signorto T.& T. VicarsLimited, Earlestown, Newton-le-Wfllows, England, a British com- Original application November 25, 1944, Serial No. 565,125, now Patent No. 2,424,949, dated July 29, 1947.

Divided and this application June 4, 1947, Serial No. 752,531. In Great Britain November 8, 1943 4 Claims.

This invention relates to improvements in the coating of articles with plastic material, as in the application of a layer of cream or soft plastic material to biscuits and is a division of application Serial No. 565,125, filed November 25,1944, issued July 29, 1947, under Patent No. 2,424,949.

An object of the invention is to enable a layer of soft plastic material of predetermined thickness and shape to be applied to a rigid article such as a biscuit without the application of friction or pressure to the articles, and irrespective of the shape or contour of the surface of the article to which said layer is to be applied.

According to this invention material is passed into the cutaway spaces of a stencil of predetermined thickness and shape thus determining a measured shape and quantity of the said material which is then exuded from the space in the stencil by means of air pressure so that the detached wad of plastic material may fall upon the surface of the article to be coated.

It will be seen that by this means the biscuit or the like article to be coated need not be in frictional or even rolling contact with the outer face of the stencil so that biscuits which may haiie an irregular or a rough upper surface can be effectively coated.

It will be preferred that plastic material be forced right through the stencil openings, the excess of material on both sides of the stencil plate being removed by scrapers prior to the exuding of the wad of material within the cutaway space of the stencil by air pressure.

The accompanying drawing is a diagrammatic sectional elevation of one form of construction according to the present invention.

A rotary hollow cylinder I has openings 2 disposed in its surface, which openings are preferably spaced evenly around the periphery of the cylinder and may be of any desired contour. A supply of plastic material 3 is fed to the interior of the cylinder or drum l by means not shown, so that during the rotation of the drum I this plastic material is forced into and through the openings 2, being scraped from the outside surface of the drum or cylinder I by a cantilever scraper 4 mounted on a pivot I5 and preferably having an arrow-head 5, so that the maximum pressure comes to bear on the stepped edge 6 of this head against the surface of the cylinder 1.

Means such as a set screw I may be provided to apply adjustable pressure to the doctor or scraper 4.

This scraper is mounted on a pivot I5 which is preferably adjustable in position relatively to the hollow cylinder.

The material 3 is, scraped from the inside of the cylindrical stencil I by means of an adjustable scraper blade 8 which may be formed as shown integral with an air pressure ejecting nozzle 9 connected to an air pressure supply pipe I0. It will consequently be seen that as the stencil I rotates relatively to the fixed scraper blades 4 and 8, material 3 will be compressed into the stencil openings and will be left as a wad within these openings only, prior to ejection from the openings 2 by the air passing out through the nozzle 9 which nozzle ma extend the full internal width of the hollow cylinder or at least slightly wider than the openings 2 in this cylinder. It will be appreciated that where a doctor or blade moves over an opening containing plastic material the effect often is to roll up the plastic material so that this becomes compressed up against a back edge of the opening but leaves the forward edge of the opening, and to avoid this effect an abutment or hump 20 is mounted on the back of the stationary nozzle 9 and scraper blade 8 forming a compression pocket I I for the plastic material and preventing this from rolling back as it comes subject to the action of the scraper blade 8.

With most plastic materials it will be found that as soon as the front edge I2 of a wad of plastic material is ejected from the opening 2 in the stencil, the rest of the wad will automatically peel away, so that it is not always essential to provide a constant air pressure either from a blower connected to the pipe I!) feeding it giving a constant air ressure.

The invention is generally applicable where it is desired to provide a thin layer of plastic material of any predetermined shape and thickness in the form of a wad to be applied to articles, and is particularly applicable for instance, by way of example, to the application of a wad or layer of cream, fruit pulp or other plastic material to biscuits in which the wad, as shown in the drawing, comes to lie upon biscuits such as I3 moving in spaced relationship on a conveyor M which is moved forward in synchronism with the rotation of the stencil drum i.

It will be appreciated that the wall of the stencil drum I Will have a thickness substantially equivalent to the thickness of the wad or layer of plastic material 3 it is desired to lay upon successive articles such as biscuits.

Air fed to the pipe l9 from a chamber 2| can be heated for instance by a steam coil or electric resistance element 22.

I declare that what I claim is:

l. A machine for applying a layer of plastic material to an article, comprising in combination a hollow rotary cylinder having openings extending through the thickness of the wall of said cylinder to form a rotary stencil plate, means to compress material fed from the interior of said cylinder into its stencil opening, scraper means to remove excess material adhering to the'outer wall and to the inner wall of said cylinder as it is displaced relatively to them, and an air nozzle disposed in operative succession to said scrapers to progressivel eject wads of plastic material confined within said openings from one side to the other of said openings while the progressively diminishing part of the wads is retained in the stencil openings by the scrapers.

2.A machine for applying a layer of plastic material to an article, comprising in combination a hollow rotary cylinder having openings extending through the thickness of the wall of said cylinder to form a rotary stencil plate, means to compress material fed from the interior of said cylinder into said openings, a scraper to remove excess material adhering to the outer wall of said cylinder as it is displaced relatively to said cylinder, a second scraper to remove excess material adhering to the inner wall of said cylinder as it is displaced relatively to said cylinder, and an air nozzle formed intergral with said second scraper in operative succession to its scraping edge.

3. A machine for applying a layer of plastic material to an article, comprising in combination a hollow rotary cylinder having openings extending through the thickness of the wall of said 1 Number cylinder to form a rotary stencil plate, means to compress material fed from the interior of said cylinder into said openings, a scraper to remove excess material adhering to the outer wall of said cylinder as it is displaced relatively to said cylinder, at second scraper to remove excess material adhering to the inner wall of said cylinder as it is displaced relatively to said cylinder, an air nozzle formed integrally with said second scraper and in operative succession to its scraping edge, means to direct a supply of air to said nozzle, and means to vary the temperature of said air supplied to said nozzle.

4. A machine for applying a layer of plastic material to an article, comprising in combination a hollow rotary cylinder having openings extending through the thickness of the wall of said cylinder to form a rotary stencil plate, means to compress material fed from the interior of said cylinder into said openings, a scraper to remove excess material adhering to the outer wall of said cylinder as it is displaced relatively to said cylinder, a second scraper to remove excess material adhering to the inner wall of said cylinder as it is displaced relatively to said cylinder, an air nozzle formed integrally with said second scraper and in operative succession to its scraping edge, means to direct a supply of air to said nozzle, and means to vary the temperature of said air comprising a heating element of the electrical resistance type disposed within the means directing said air supply.

PERCY WHITE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Marsden Feb. 22, 1938 Gromm Apr. 1, 1941 FOREIGN PATENTS Country Date France Oct. 13, 1925 Number 

